Question

A thin copper wire of length l metre increases in
length by 2% when heated through 10°C. What is
the percentage increase in area when a square
copper sheet of length l metre is heated through
10°C?
(1) 4%
(2) 8%
(3) 16%
(4) None of these
​

Answer 1

Hola mate here is your answer :-

Option A is the correct answer

(1) Since percentage increase in length = 2 %

Hence, percentage increase in area of square sheet

=

2

×

2

%

=2×2% = 4%

Hope it helps!!✌️✌️✌️

Answer 2

Given:

Increase in the length of the copper wire = 2%

Temperature = 10°C

To find:

The percentage increase in area of the square copper sheet

Calculation:

Area of the square = l²

Percentage increase in area of the square = 2(Δl/l)

                                                                       = 2(2%)

                                                                       = 4%

The percentage increase in area of the square copper sheet is 4%